Lateral semiconductor layers have different band gaps in such a way that a two-dimensional electron gas can form in their semiconductor depletion layer, wherein between source electrode contact areas and drain electrode contact areas a current can flow upon application of a voltage between a source metalization and a drain metalization through the lateral semiconductor depletion layer on account of the two-dimensional electron gas. The current intensity in a channel region between the source electrode contact areas and the drain electrode contact areas can be controlled via gate electrode contact areas by means of a gate voltage and the manifested field effect.
Multilayered metalizations are applied on the source electrode contact areas, the drain electrode contact areas and the gate electrode contact areas, wherein a topmost power metalization is required only on the source electrode contact areas and the drain electrode contact areas, which, however, are spaced apart from one another and intermesh in a toothed fashion without the teeth touching one another. The intermeshing teeth spaced apart from one another are also called contact fingers and have a rectangular contour in conventional field effect power transistors, wherein strip-shaped metalizations of the gate electrode contact areas are arranged below the metalization of the source electrode contact areas and in a manner insulated from the latter by an insulation layer.
Such a metalization having rectangular contact fingers or teeth is known from the document U.S. Pat. No. 7,550,821 B2. One disadvantage of the elongated contact fingers is that the current density decreases from the contact finger foot to the contact finger tip, such that the width in the region of the contact finger foot limits the maximum current density of the metalization of the source electrode contact areas and of the drain electrode contact areas, while the width of the rectangular contact finger tip is overdimensioned.